Spectrum attributes of frequency-steerable phased array antennas

Abstract

When considering phased array radar systems it is important to consider the possible differences in the spectral content of radar emissions when comparing boresight to off-boresight. This detail is important as it can accentuate potential electromagnetic interference (EMI) effects between radar and other devices competing for space in a crowded spectrum. In order to analyze the potential impact of off-boresight radar emissions to other electronic devices, a MATLAB and electromagnetic model of a simple eight element slotted waveguide linear array operating at 3.5 GHz was simulated with an element spacing of a half-wavelength. The model was stimulated utilizing continuous wave (CW), pulsed amplitude, and linear Frequency Modulated Continuous-Wave (FMCW) waveforms. The spectral content of these emissions in the far-field was assessed at a variety of angles with respect to boresight. It was concluded that the eletromagnetic emissions power may be under measured if out of band emissions of a waveguide slot array are measured only at boresight resulting in compliance testing issues. This could result in the interference to other electronic devices being underestimated.